QIKCOM
RE-CONFIGURABLE TRANSPONDER
MODULE
Michael Segalla and Cole Skinker
Advisor: Bob Bruninga
AIAA YPSE Conference
November 7, 2014
Problem Background
 Automatic Packet Reporting System Protocol
(APRS) is the primary communications protocol
used by USNA satellites
 With long development time, the response time
for short fuse launch opportunities is limited
 USNA only has one APRS satellite in operation
currently
2
Slow Development Time
 PCSAT: communications satellite,
4 years to design and deliver for
launch
 Still operational
 PSAT: communications CubeSat,
 Time to deliver: ~6 years
 Currently in work – manifest 2015
 PCSAT2: communication payload,
2 years, attached to ISS
 Returned to Earth
3
Automatic Packet Reporting System
(APRS)
4
Host Satellite Opportunity
 A company has offered to house a USNA
payload on a host satellite
 Host satellite provides:
 Power
 Thermal control
 Attitude determination system
 Location for mounting interface
Requirements: Host
Host Requirements
Voltage
28V
Temperature Range
-20 °C - 60°C
Housing Structure
Size
No larger than 4” x 6”
Communications
Reliable dual-antenna
deployment system
6
Requirements: USNA
USNA Requirements
Users ~per minute
6
Packets ~per pass
51
Operational Availability
Dependent on host
specs
Host provides Temp
Thermal Control : From
Control within Min / Max
Host S/C
Range
Delivery
Lifetime
Reliability
confidence
Schedule
Threshold
29-Dec
5 months
Objective
15-Dec
4.5 months
90
90
QIKcom Objectives
 Produce a transponder for Amateur Satellite
Service within 5 month period
 Provide an on-board beacon to actively notify
wilderness terrestrial amateur radio users in
North America when satellite is available
APRS Integrated Network
8
Solution
 USNA shall combine following COTS and self-designed
components to produce module
COTS:
 MT-TT4 transponder:
 Micro-Amp 3 power amplifier: necessary to boost antenna power
 Mictro-Trak 8000 FA communications beacon: operates on terrestrial
frequency, notifies users of satellite overhead
Designed components:
 Antenna deployment board
 EPS regulating board
EPS Board
9
Concept of Operations
Beacon notifies users when
QIKcom is overhead on
terrestrial frequency.
Users tune to space
frequency
QIKcom Transponder module
10
Satellite positioned in
launch vehicle
Launch vehicle proposed
take-off: March 2015
Transponder
module placed
inside interface
structure
Module placed on
NovaWurks
Satellite
11
NuvaWorks Satellite
deployed from ISS into
4-month mission orbit
Rocket Payload
rendezvous with ISS
Launch March 2015
12
System Overview
 Electrical Power System: 28 Volts supplied by host
spacecraft
 Attitude Control: Host satellite orients satellite
 Thermal Control: -20 °C ↔ 60 °C
Components assembled together on
working board
13
Electrical Power System
Power Budget
Power Budget
Load
Operating
Voltage
I pk (mA)
Duty
Cycle
Beacon (Standby)
12
15
98.3%
14.75
7.14
7.02
Beacon (TX)
12
1000
1.70%
17
476.2
8.1
MTT4 (TX-users)
5
280
1.7%
4.8
55.6
0.95
MTT4 (TX-Telemetry)
5
280
4%
11.2
55.6
2.2
MTT4 (RX)
5
45
100%
45
8.93
8.93
Power Amp (TX)
12
1000
10%
100
476.2
47.62
1079.6
74.8
Total
28 V - Peak Power (W)
30
28 V – Average Power (W)
2.1
I avg (mA) 28V Ipk
(mA)
28V Iave
(mA)
PCB Board Design
Power provided by host bus. Pavg of 2W consistent with 1U
CubeSats, however all is dedicated to telemetry rather than other
subsystems
14
Telemetry and Link Budget
Frequencies
145.825 MHz - 4 Watt - AX.25
Telemetry downlink
ITU Emission Designator
16K0F1D, FM, 1200-9600
baud AX.25 data rate
Antenna
Cross polarized 1/4 wave
whips
Power transmitted
6 dBW
Transmitter Gain
0 dB
Receiver Gain
15 dB
Space Loss at max range
of 3000 km
Computed Receiver
Power
RX threshold
Margin at horizon for
Oscar class sation
Margin for hand-held
omni-antenna
TT&C and Downlink
Operations
United States Naval
Academy
Mission Downlinks Amateur Radio Operators
-145.5 dB
-127.5 dBW
-146 dBW
18.5 dB
3.5 dB
3.5 dB sufficient margin for any amateur operator to communicate
with QIKcom if within view
15
Antenna Deployment System
 Orthogonal dual
antennas
 Lone resistor connected
with fishing wire
 Requires consistency: 50
successful tests for
confidence
 Stacked housing
Antenna deployment system
16
Thermal and EPS Sensors
5 Sensors:
•
•
2 Thermistors located on MTT4 and
power amplifier, monitor safe
operating temperatures
1 Voltage and 1 current sensors to
monitor input from host bus
12V sensor to monitor proper
regulation of power to power amplifier
and beacon
80
Temperature
•
60
40
20
0
-20
-40
•
Tests completed to date:
• Thermistor Calibration
-60
0

200
400
Count
600
800
Recent test:
Thermistor Calibration
17
CONCLUSIONS
18
Summary
Host Requirements
Parameter met?
Voltage
28V
Yes
Temperature Range
-20 °C - 60°C
Requires Testing
Housing Structure Size
No larger than 4” x 6”
Yes
Communications
Reliable dual-antenna
deployment system
Requires Testing
 COTS and USNA components combined in rapid
manner
 Turnaround of 5 months achieved
 Reduced lead time by 1/4 of previous
comparable USNA satellite (PCSAT2)
 Satellite enthusiasts notified when satellite
overhead
 Link budget indicates beacon sufficient
19
Future Schedule
Integrate PCB chip
Test (Vibration / Thermal)
Delivery (Dec. 29th)
Launch (March)
20
Acknowledgements
CDR Robert Bruninga, USN (ret.)
Assistant Professor Jin Kang
Thank you for your time
Questions?